I Can�t Keep Up With All The Formats II
by Roger Nichols
The formats we have not covered yet include cassette, multi-track cassette,
8-track, EL-cassette, PCM-F1, DAT, DBX, 3M, CD, PD, DASH, Akai, MP-3, DSD,
DTS, AC-3, MLP, MPEG-2, DVD, DV, DV-PRO, DSD, DVD-A, SD II, WAV, AIFF, Digital
Radio, and, by the time this reaches the newsstand, probably a few more.
8-Track Tapes
I really don�t want to talk about 8-track tapes very much. Lear introduced
an endless-loop 8-track tape playback system that used 1/4� tape in a
plastic cartridge. Four stereo programs ran in the same direction. At the
end of the loop there was a piece of metal foil that moved the stereo playback
head to the next pair of tracks. It therefore took four passes through the
loop to play an entire album. At the end of the fourth pass the tape head
moved back up to the first pair and started the album over. In 1999 I still
saw 8-track tapes for sale in a truck stop in Arkansas. I don�t stop
there anymore.
Cassettes
�Portable� was the key word in the 70�s. Sony had developed
the 3/4� videotape cassette and was about to introduce the Betamax 1/2�
videocassette to the consumer video market. Philips came up with a format
called the audiocassette. It housed 1/8� reel-to-reel tape running 1
7/8 ips into a closed plastic shell. Drop the cassette into a player and press
play. No tape threading, no muss, no fuss. The heads did not move and go out
of alignment as easy as they did in the 8-track format. The audiocassette
was an instant success. To top it all off, the cassette was recordable. You
could now take your music with you.
There were actually four tracks on the cassette. Two channels played in each
direction. The cassette players had an �auto reverse� feature that
would play side 2 of the cassette without turning the tape over. New tape
formulations were developed with smaller particles to help with the high frequency
response at such slow tape speeds. A Japanese company named Nakamichi produced
a cassette deck that would record at 3 3/4 ips for more high fidelity, but
Philips sued to make them stop. A Philips suit also stopped another format
called EL-cassette. The EL-cassette used a larger cassette (almost the size
of a Betamax cassette) with 1/4� tape-recorded at a higher speed.
The Porta-studio
Since the cassette tape had four tracks on it, why not record them all in
the same direction and have a four-track studio at home? Porta-studios started
popping up everywhere. Because the cassette was not used for a consumer format,
Philips finally let the porta-studio manufacturers raise the speed limit to
3 3/4 ips. Some manufacturers even came out with eight track porta-studios.
There was not a musician on the planet that did not own at least one incarnation
of the porta-studio.
Digital Audio
Digital audio was alive and well in the telephone and airline industries.
Hundreds of phone calls could be digitized and combined onto one wire, and
then split apart at the receiving end. All 12 music channels offered to you
at your seat on an airline were digitized, multiplexed, and sent down one
wire to all of the seats. You selected the channel and that segment was picked
out of the data stream and converted to analog right at your seat. The quality
was low, but the method worked well.
SoundStream
In the late 70�s a company named SoundStream started dabbling in digital
audio. They used a reel-to-reel data recorder to put the eight channels of
audio data on tape. Classical recordings were the first to embrace the format.
A low noise floor and wide dynamic range were perfect for the classical productions.
In 1980 we were just finishing up the Steely Dan �Gaucho� album
and decided to listen to the SoundStream recorder as a potential mix medium.
We dumped a rough mix onto the machine and then Donald Fagen did a vocal overdub
on it. The sound of the vocal was to be the deciding factor in choosing the
format. When we played it back there were strange high frequency artifacts
that didn�t quite meet the Steely Dan level of acceptance, but it was
pretty damn good. We decided, �Not for this album, but we are sure going
to be looking at the digital format for the next album.�
Video Based Digital Audio
Sony, at about the same time, was developing a digital format using videotape
as the storage medium. The first Sony recorder to offer digital audio recording
was the PCM-10. It recorded 14bit stereo on 3/4� videotape. There was
a stereo store in New York called Crazy Eddie�s that had one. I was in
there often drooling over the machine, but the $7,000 price was a little steep
in 1980.
In Japan the EIAJ adopted a standard for video based digital audio. The first
consumer machine to enter the market was made by Technics. It recorded 14bit
stereo digital audio on VHS tape. The machine looked like a giant front-loading
cassette machine that used VHS size cassettes. Some record companies actually
sold pre-recorded tapes in this format. You could only find them at the hi-fi
stores that sold the machine. Sony, Sansui, Mitsubishi, Nakamichi and other
Japanese companies started producing stand-alone encoder/ decoder boxes that
could be used with existing videotape machines to record digital audio. All
of them were 14bits (the EIAJ format), but Sony upped the ante.
Some of the data recorded on the videotape was for error correction, which
compensated for dropouts on the videotape. Video machines had there own dropout
compensation that would substitute the previous line of video if a dropout
occurred. For video applications this is good. You can�t see one doubled-up
video line when 30 frames per second are screaming by on the TV, but when
using the format for digital audio, too much data is lost when the whole line
is repeated. You needed enough error correction to get the lost data back,
so 14bits was all that would fit. Sony put a switch on all of their Beta decks
labeled �PCM� that you switched when using the deck for digital
audio. The switch turned off the video dropout compensator and let the digital
audio encoder/ decoder perform any error correction. Now the decoder only
had to recover from small errors and not a whole line's worth of errors. You
didn�t need as much error correction so you had room for 16bits of audio.
The Sony (and Nakamichi, made by Sony) PCM encoders had a switch that let
you choose between 14bits and 16bits when recording digital audio. I got the
first Sony PCM-F1 in the US in February 1982. We used it to record some location
party sounds for the song �Ruby� on Donald Fagen�s Nightfly
album.
Digital audio was now portable. The Sony PCM-F1 worked on 12volts dc. There
was a portable Betamax that also ran on 12volts dc. With these two machines
and 4,375 car batteries you could record digital audio anywhere. The Sony
F1 format was the only portable digital audio format until the DAT machine
showed up in 1989. I use the F1 and a Sony portable console to record five
John Denver concerts in the Soviet Union in 1986. Until DAT, I used the F1
as one of my mix formats.
3M Digital Mastering System
The Ry Cooder Bop Till You Drop album was the first digitally recorded pop
album. It was recorded on the 3M 32-track digital recorder at Amigo studios
in North Hollywood California. We booked the Village Recorder in 1981 to cut
tracks for Nightfly and decided to try the 3M digital machine. We ran a Studer
A-80 24-track analog machine in parallel with the 3M for the test. After the
band laid down a take we performed an a-b-c listening test. The analog and
digital machines were played back in sync while the band played along live.
We could compare the analog machine, the digital machine, and the live band.
The closest sound to the live band was the 3M digital machine. We re-aligned
the Studer and gave it one more chance. The 3M was the clear winner. We rolled
the Studer out into the street, (just kidding) and did the rest of the recording
on the 3M 32-track machine. When it came time to mix, we mixed to the 3M 4-track
machine.
The 3M 32-track used 1� digital tape and the 4-track used 1/2� digital
tape. They both ran at 45 ips. I guess 3M wanted to sell you lots of tape.
The digital audio was recorded at 50kHz 16bits. There were no 16bit converters
in 1981, so the 3M system used a 12 bit Burr-Brown converter and 4bits of
an 8bit converter as gain-ranging to produce the 16bit results. The �brick
wall� analog filters on the 3M machine hand-wound coils and took up most
of a circuit board. They sounded good.
The biggest drawback to the 3M system was the minimal error correction. After
a couple of months working on the same piece of tape, the error count started
to rise above the correctable level. There were adjustments on the front of
the machine to fine tune the decoding of the data recorded on tape. You could
adjust each track for the least amount of correctable errors and then transfer
the tape digitally to another 3M machine. You now had a clean error-free tape
to work on for a couple of months.
Enough for now
Digital audio was on the scene for good. Mitsubishi, Sony, Studer, Otari and
Tascam would soon jump into the pro digital multi-track market. CDs were coming
and there was no stopping digital audio. Next time we will continue our little
format saga, so stay tuned.
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